In a camera module used in a digital camera or the like, according to a demand for a reduction in thickness and a reduction in size, a distance between a lens and an imaging element (a focal length) tends to be reduced as much as possible. In the past, to reduce the distance between the lens and the imaging element, a reduction in size of pixels is advanced. A reduction in the focal length of the lens is performed by, for example, increasing an angle of the lens or using a high refractive-index material. However, as the pixels are further reduced in size, an SN ratio is deteriorated because of insufficiency of sensitivity due to a decrease in a light reception amount per one pixel or because of a decrease in the number of saturated electrons. Further, there is a limit in a reduction in the focal length through selection of a material of the lens and design of the lens.